Hawaiian Electric Co. has given the green light to nearly 10,000 rooftop solar systems on Oahu this year, and still the rush of applicants outpaces what the utility can approve.

More than 2,000 solar system applications are awaiting HECO’s authorization as residents push to get connected before a solar incentive program changes.

“It was kind of a race to the finish line,” said Rich Taylor, project developer at PhotonWorks Engineering LLP, a Hawaii solar contractor.

The state Public Utilities Commission might rule in the next few weeks on a HECO proposal that would reduce the amount solar owners are credited for the excess energy their PV systems send to the grid, a system known as Net Energy Metering.

“There has been a surge in NEM applications due to the uncertainty surrounding the future of NEM,” said Leslie Cole-Brooks, executive director of Hawaii Solar Energy Association, an industry lobbying group. “Customers who want to install solar are trying to get their applications in.”

HECO has approved 9,673 solar system applications this year. Of those, 5,644 were submitted before the start of the year. The record year for approvals was 2013 when 14,629 applications were given the go-ahead.

“HECO is approving systems faster than a year ago, but not as quick as our customers demand,” said Chris DeBone, managing partner at Hawaii Energy Connection, a solar installer.

Taylor of PhotonWorks said he also has seen an increase in approvals. More than 50 percent of his customer applications have been approved this year. Last year fewer than 20 percent of his solar systems were approved.

“Compared to this time last year, that is a huge increase in approvals,” Taylor said.

The utility has been under pressure to approve systems faster. In February PUC Chairman Randy Iwase met with HECO CEO Alan Oshima and said that HECO agreed it has a “duty” to approve solar systems.

Even with a faster approval rate, a large backlog remains. As of Sept. 15, 2,375 applications on Oahu awaited approval, according to a weekly progress report submitted by HECO to the state PUC.

“There have been constantly large numbers of applications added, and it is hard for HECO to keep up,” said Colin Yost, principal at RevoluSun, which installs rooftop solar.

The average time to approve an application is 59 days, according to HECO. But the outliers have been waiting much longer, some for over a year.

In some areas the average wait is 254 days. Those are the neighborhoods that already have a high number of solar systems; 390 applicants await approval in those areas.

Some areas where solar companies are finding it difficult to get rooftop photovoltaic approved are Mililani, portions of the Waianae Coast and sections of Kailua, Kaneohe and East Honolulu; those neighborhoods have reached the maximum limit the utility said it can handle.

“Interest in rooftop PV remains strong, and we have continued to receive thousands of applications,” said Darren Pai, HECO spokesman. “Thousands have been approved, but there are applications that are still going through various stages of the review and approval process. We’re following the timelines and processes approved by the PUC and working as quickly as possible to review and approve applications.”

John Wacker, a Hawaii Kai resident who has been waiting for approval since November, said he is still hopeful but is stressed out by the delay.

“It sucks,” said Wacker. “It is inconvenient because it is open-ended.”

Wacker lives in a neighborhood with 250 percent solar saturation, according to HECO.

“I can understand the saturation,” Wacker said. “We have 12 houses in the cul-de-sac, and eight already have solar.”

While local homeowners waiting for approval might be frustrated, HECO has a reputation outside the state for pushing the frontier in solar adoption, said Bryan Hannegan, associate laboratory director for Energy Systems Integration at the Colorado-based National Renewable Energy Laboratory.

“It used to be that utilities didn’t even go beyond 100 percent,” Hannegan said. “Hawaiian Electric is the only one to my knowledge that goes to 250 percent today.”

HECO is “setting a way for the mainland to follow,” he said.

On Oahu, 48,743 PV systems have been installed on residential homes. Combined, HEI’s utility subsidiaries — including the Maui and Hawaii island power companies — have approved more than 71,000 rooftop solar systems among a total of 450,000 customers.

Since 2012, the utility said, it has approved 1,000 applications in high-saturation areas. Of the applications approved this year, 22 percent were in high-saturation areas.

Pai, the HECO spokesman, said the utility is working on new solutions, like battery storage systems and monitoring technology for PV systems that can help speed up the review process for new solar systems.

“Developing a smart grid is an essential part of our plans to achieve a clean energy future,” Pai said. “It will help integrate greater amounts of renewable energy and improve our ability to add more rooftop PV in areas with high concentrations of solar power.”

Until those upgrades are made, some residents are left anxiously waiting for an answer.

“I’m feeling like a racehorse and the gate is getting ready to go,” Wacker said. “But I don’t know when the race is going to start.”